ECO3101: Intermediate Microeconomics

Course Description

ECO3101, Intermediate Microeconomics, is the theory course of the economics major. It takes the intuitions introduced in principles of microeconomics and rebuilds them as formal models: consumer choice derived from preferences and budget constraints, firm behaviour derived from production technology and cost minimisation, and market outcomes derived from the interaction of the two under varying competitive conditions.

The University of West Florida's description tracks the standard sequence: "economic activity of individual economic units as consumers, resource owners and business firms. Analysis of consumer motivation as the basis of demand theory. Study of how business firms determine what to produce, how to produce at least cost, how to maximize profits, and how to distribute products. Monopoly, oligopoly, imperfect competition, and the different market conditions for resources are studied to present how the optimum use of each resource is determined by the firm." The University of Florida's is more compact — "nature, scope, and purpose of economic analysis. Examines the theory of consumer behavior, production, costs, firm behavior, and the allocation of resources."

What changes from principles is the method. Principles courses argue in words and graphs; intermediate micro argues in constrained optimisation. Students who found principles straightforward sometimes find this course a genuine step up, because the answer is now derived rather than described.

ECO3101 is offered at approximately 12 Florida institutions, all of them universities — it is a 3000-level course and does not appear in the Florida College System's lower-division inventory. It is required in essentially every economics major and in most business economics and finance concentrations.

⚠ Credits and the calculus requirement diverge — check before you enrol or transfer

This is the practical warning for this course, and it is not visible from the number:

• University of Florida — 4 credits, calculus required. Prerequisites are ECO2023 and MAC2233 (survey of calculus) or a higher-level calculus course, or AEB3103. The extra credit reflects the extra analytical load.
• Florida State University — 3 credits. Prerequisites ECO2013 and ECO2023.
• University of Central Florida — 3 credits. Prerequisites ECO2013 and ECO2023.
• University of West Florida — 3 credits. Prerequisites (ECO2013 and ECO2023) or ECO3003 — no calculus prerequisite listed.

Two consequences follow. First, a 3-credit ECO3101 transferred against a 4-credit ECO3101 can leave a student a credit short inside the major. Second, and more substantively, the mathematical level differs. A section with a calculus prerequisite will derive marginal conditions by differentiation and will treat the Lagrangian method as ordinary; a section without one will work the same results graphically and algebraically. Both are legitimate intermediate microeconomics, but a student moving from the second kind into a programme built on the first — particularly one contemplating graduate study in economics — should expect a gap and plan to close it. This guide is written to 3 credits and 45 contact hours, the majority pattern, and flags the calculus-based variant throughout.

Learning Outcomes

Required Outcomes

• Explain the economic problem of scarcity and constrained choice, and formulate an economic question as an optimisation problem with an objective and a constraint.
• Represent consumer preferences with indifference curves and utility functions, and explain the assumptions (completeness, transitivity, monotonicity, convexity) that make the representation possible.
• Derive the consumer's optimal bundle from a budget constraint and preferences, and interpret the tangency condition as equality of the marginal rate of substitution and the price ratio.
• Derive individual and market demand curves from consumer optimisation, and decompose the effect of a price change into substitution and income effects.
• Calculate and interpret elasticities — price, income and cross-price — and connect elasticity to revenue and to incidence.
• Apply consumer theory to labour supply, intertemporal choice and saving, and choice under uncertainty including expected utility and risk aversion.
• Represent production technology with production functions and isoquants, and explain returns to scale and the marginal rate of technical substitution.
• Derive cost functions from cost minimisation, and distinguish short-run from long-run costs, fixed from variable, and total from average and marginal.
• Derive the competitive firm's supply curve from profit maximisation, and identify shutdown and exit conditions.
• Characterise short-run and long-run equilibrium in perfectly competitive markets, and explain the role of entry and exit.
• Analyse monopoly: the profit-maximising output and price, the deadweight loss, price discrimination of the first, second and third degree, and the case for and against regulation.
• Analyse monopolistic competition and oligopoly, including the Cournot, Bertrand and Stackelberg models.
• Apply basic game theory: normal-form games, dominant strategies, Nash equilibrium, and sequential games solved by backward induction.
• Analyse factor markets and derive the demand for labour and other inputs from the firm's optimisation problem.
• Evaluate market outcomes for efficiency using consumer and producer surplus, and explain the first welfare theorem and its assumptions.
• Analyse the principal sources of market failure — externalities, public goods, and asymmetric information (adverse selection and moral hazard) — and evaluate the standard policy responses.
• Evaluate the welfare effects of specific interventions: taxes, subsidies, price ceilings and floors, quotas and tariffs.

Optional Outcomes

• Solve constrained optimisation problems using calculus and the Lagrangian method — required in calculus-based sections such as UF's, optional elsewhere.
• Derive and apply duality results: expenditure minimisation, Hicksian demand, Roy's identity and Shephard's lemma.
• Analyse general equilibrium in an exchange economy using the Edgeworth box, and state the two welfare theorems.
• Analyse mechanism design and auction formats.
• Apply behavioural economics: bounded rationality, prospect theory, framing, present bias, and the departures from the standard model.
• Analyse contracts, principal-agent problems and incentive design.
• Apply the tools to a policy area — health economics, environmental economics, labour economics, industrial organisation — through a case study or paper.
• Use spreadsheet or statistical software to solve and simulate microeconomic models.

Major Topics

Required Topics

• The economic approach: scarcity, opportunity cost, marginal analysis, models and their assumptions; positive versus normative analysis
• Supply and demand review, market equilibrium, comparative statics
• Elasticity: price, income and cross-price; determinants; revenue and tax incidence
• Consumer preferences: axioms, indifference curves, utility representation, marginal rate of substitution
• Budget constraints and consumer optimisation; corner solutions
• Comparative statics of consumer choice: income and price changes, Engel curves, normal and inferior goods, Giffen goods
• Substitution and income effects: Slutsky and Hicksian decompositions
• Deriving market demand; consumer surplus as a welfare measure
• Applications of consumer theory: labour supply, intertemporal choice, choice under uncertainty and risk aversion
• Production: technology, production functions, marginal and average product, isoquants, returns to scale
• Costs: cost minimisation, the expansion path, short-run and long-run cost curves, economies of scale and scope, sunk costs
• Perfect competition: profit maximisation, the firm's supply curve, shutdown and exit, short-run and long-run industry equilibrium
• Efficiency of competitive markets: producer surplus, total surplus, the first welfare theorem, deadweight loss from intervention
• Monopoly: market power, marginal revenue, profit maximisation, deadweight loss, natural monopoly and regulation
• Price discrimination: first, second and third degree; bundling and two-part tariffs
• Monopolistic competition: product differentiation and long-run equilibrium
• Oligopoly: Cournot, Bertrand, Stackelberg, collusion and cartel stability
• Game theory: normal and extensive form, dominant strategies, Nash equilibrium, repeated games, credible commitment
• Factor markets: derived demand for labour and capital, marginal revenue product, monopsony
• Externalities: Pigouvian taxes, tradable permits, the Coase theorem
• Public goods: non-rivalry, non-excludability, free riding, and provision
• Asymmetric information: adverse selection, signalling, screening, moral hazard, principal-agent problems

Optional Topics

• Calculus-based optimisation and the Lagrangian method (required in calculus-based sections)
• Duality: expenditure functions, Hicksian demand, Roy's identity, Shephard's lemma
• General equilibrium, the Edgeworth box, Pareto efficiency and the two welfare theorems
• Auctions and mechanism design
• Behavioural economics and its challenges to the standard model
• Contract theory and incentive design
• Applied policy modules: health, environmental, labour or urban economics
• Introductory industrial organisation: entry deterrence, antitrust, merger analysis
• Computational or spreadsheet-based model solving and simulation

Resources & Tools

• Microeconomics (Pindyck & Rubinfeld) is the most widely adopted text for this course in Florida and nationally; it is accessible without calculus while supporting a calculus-based treatment in its appendices.
• Intermediate Microeconomics: A Modern Approach (Varian, W. W. Norton) is the other standard, and the one most often used where the course is preparation for graduate study; the companion Workouts in Intermediate Microeconomics is where the actual learning happens for most students.
• Microeconomics (Besanko & Braeutigam), Intermediate Microeconomics and Its Application (Nicholson & Snyder) and Microeconomics (Perloff) are common alternatives; Perloff is notable for its use of real empirical applications.
• The Economics Network and MRU (Marginal Revolution University) provide free video explanations that Florida instructors frequently point students toward; MRU's intermediate micro sequence maps closely onto a standard syllabus.
• Mathematics support: Mathematics for Economists (Simon & Blume) is the reference for students who need to build the calculus foundation, particularly those aiming at graduate work. Khan Academy covers the differentiation and constrained optimisation needed for a calculus-based section.
• Software and tools: spreadsheets (Excel Solver for constrained optimisation), Desmos and GeoGebra for interactive graphing, and R or Python where the course includes simulation. Graduate-track students often begin using LaTeX around this point.
• Data sources for applied work: FRED (Federal Reserve Bank of St. Louis), the Bureau of Labor Statistics, the Bureau of Economic Analysis, and for Florida specifically the Florida Department of Economic Opportunity (now the Department of Commerce) labour market statistics and the Florida Office of Economic and Demographic Research.
• Professional context: the American Economic Association, and for the actuarial and financial pathways the Society of Actuaries, the Casualty Actuarial Society and the CFA Institute.

Career Pathways

• Economist — SOC 19-3011. A graduate degree is effectively required; this course is where the decision to pursue one is usually made, and performance in it is what a graduate admissions committee reads.
• Financial Analyst and Investment Analyst — SOC 13-2051. The most common private-sector destination for economics majors; the CFA charter is the standard credential.
• Market Research Analyst — SOC 13-1161. Demand estimation and elasticity are used directly.
• Data Analyst and Data Scientist — SOC 15-2051. Economics graduates with econometrics and programming are competitive here, and the optimisation framework transfers well.
• Actuary — SOC 15-2011. Requires the SOA or CAS examination sequence; the choice-under-uncertainty and risk material in this course is directly relevant.
• Management Consultant and Business Analyst — SOC 13-1111.
• Policy Analyst and Regulatory Economist — SOC 19-3011 and 13-1111, in state agencies, legislative research offices and regulatory bodies.
• Pricing and Revenue Management Analyst — SOC 13-1111 and 13-2099. Price discrimination and two-part tariffs are not academic here: airline, hotel, cruise and theme park pricing are built on exactly this material, which makes it an unusually applicable topic in the Florida economy.
• Lawyer — SOC 23-1011. Economics is among the strongest undergraduate preparations for law school, and antitrust, regulatory and law-and-economics practice use this material directly.
• Florida employers and settings of note: the hospitality and tourism sector, where revenue management is a large professional function — Walt Disney World, Universal, Marriott, Hilton and the cruise lines headquartered in Miami (Carnival, Royal Caribbean and Norwegian); financial services concentrated in Miami, Jacksonville, Tampa and West Palm Beach, including Raymond James (St. Petersburg), Citi and JPMorgan operations in Tampa and Jacksonville; the health insurers and managed care organisations with major Florida operations; the Federal Reserve Bank of Atlanta's Miami and Jacksonville branches; and on the public side the Florida Office of Economic and Demographic Research, the Legislature's Office of Program Policy Analysis and Government Accountability, and the state's water management districts and regional planning councils.

Special Information

Position in the curriculum

ECO3101 is normally taken in the sophomore or junior year, immediately after the principles sequence, and it is a prerequisite for most upper-division economics electives — industrial organisation, labour, public, health, environmental and international economics all assume it. It is usually taken alongside or shortly before intermediate macroeconomics (ECO3203) and econometrics (ECO4421 or equivalent). For students transferring from a Florida College System A.A., it is the first true major course after transfer, which makes it the course where the difficulty step from principles is felt most sharply.

Prerequisites narrative

The principles sequence is universal: ECO2013 (macroeconomics) and ECO2023 (microeconomics), or an equivalent survey such as ECO3003 at UWF. The genuine divergence is mathematics. UF requires MAC2233 or a higher calculus course; FSU, UCF and UWF list no calculus prerequisite for ECO3101 itself, though their economics majors generally require calculus somewhere in the degree. Statistics (STA2023) is required by the major at most institutions and is a practical prerequisite for the econometrics course that follows.

The advice that follows from this: take calculus even where the course does not require it. Intermediate micro is where the calculus pays off, graduate study in economics is calculus-intensive from day one, and the quantitative career paths — actuarial, data, finance — all assume it. A student who takes the non-calculus route and later decides on graduate school will need to backfill.

Course format and workload

Three credits and approximately 45 contact hours at most institutions, four credits at the University of Florida. Assessment is problem-set driven, with examinations that require deriving results rather than recalling them. This is a course where the gap between reading the textbook and being able to work the problems is unusually wide; the standard advice — work every problem in Workouts or the equivalent, without looking at the solution first — is standard because it is correct. Plan for six to ten hours per week outside class. Online sections exist but are less common than for lower-division economics, and the material rewards the ability to ask a question in real time.

Transfer and articulation

ECO3101 is a 3000-level SCNS course. The number is recognised statewide, but upper-division credit is not covered by the A.A. transfer guarantee and applicability inside the major is the receiving department's decision. Two specific risks, both discussed above: the 3-versus-4-credit difference, which can leave a transfer student short of the major's credit total, and the calculus-level difference, which is invisible on a transcript. Note also that this course is not available before transfer from a Florida College System institution — the principles courses ECO2013 and ECO2023 are the lower-division common prerequisites, and they transfer cleanly; ECO3101 belongs to the junior year.

Course-code variations across Florida

The relevant family: ECO2013 and ECO2023 (principles of macro and micro — the prerequisites, taken at any Florida institution); ECO3003 (a combined or survey intermediate course accepted in place of the principles pair at UWF); ECO3101 (this course); ECO3203 (intermediate macroeconomics, the companion); ECO3106 (behavioural economics, a different course despite the adjacent number); ECO4400-range game theory courses; and ECO4421/ECO4933-range econometrics. Managerial economics appears under ECP or GEB prefixes in business programmes and is not equivalent to ECO3101 — it is applied and less formal, and an economics major generally cannot substitute it. Agricultural and resource economics equivalents appear under AEB, and UF explicitly accepts AEB3103 as an alternative prerequisite path.

AI Integration

Intermediate microeconomics is a derivation course, which puts it in an unusual position with respect to AI tools: they are genuinely capable at the mechanical part of the work and genuinely unreliable at the part that constitutes understanding.

Where AI helps. Language models are effective at explaining a step you are stuck on, at checking algebra, at generating additional practice problems in the same form as an assigned one, and at producing worked variations so that you can see which features of a problem matter. For students building the calculus fluency the course assumes, an AI tutor that will patiently re-derive a first-order condition five different ways is a real asset. Models are also useful for translating between representations — turning a verbal description of a market into a formal model, or explaining what a Lagrange multiplier means economically.

Where AI fails. Models make sign errors and algebraic slips in multi-step derivations, and they present them with the same confidence as correct work — which is the specific danger in a course where an incorrect intermediate step yields a plausible-looking final answer. They frequently misapply a model outside its assumptions: applying competitive market conclusions to a monopoly problem, or ignoring a corner solution. They are weak at the comparative statics that intermediate micro is really about — reasoning about what happens to the equilibrium when a parameter changes, rather than solving a single numerical instance. And they will produce an economically confident interpretation of a result that the mathematics does not support.

The economist's responsibility. The point of this course is to be able to derive a result and to say why it holds. An answer you cannot reproduce on paper is not knowledge you have. The practical test is simple: after using a tool to get unstuck, close it and work the problem again from a blank page. If you cannot, you have watched a derivation rather than learned one — and the examination, which is closed-book at most institutions, will find that out.

AI as subject matter. The economics of AI is now a live applied field and instructors increasingly use it for examples: algorithmic pricing and the question of whether pricing algorithms can sustain tacit collusion without communication (an oligopoly and antitrust question that sits squarely in this course's territory); AI's effect on labour demand and the skill premium, which is factor-market analysis; the market structure of AI itself, with very high fixed costs and near-zero marginal costs, which is a natural monopoly problem; and the information-economics questions raised by recommendation and matching systems. These make good essay and problem topics precisely because the course's standard tools apply to them directly.

Academic integrity. Problem sets are formative — they exist so that you arrive at the examination able to do the work. Policies vary by institution and instructor, and a common arrangement permits AI for checking and explanation while prohibiting it for producing submitted solutions. Read the syllabus, and note that in a course assessed largely by closed-book examination, over-reliance on AI on homework is self-punishing regardless of policy.